One researcher says the debate over whether oilsands development in northern Alberta is polluting surrounding lakes is now completely over.

Queen’s University biologist John Smol is one of the authors of a report that shows levels of toxic hydrocarbons in six lakes in the region are as much as 23 times higher than they were before the mines were built.

Smol says the door is now shut on industry and government suggestions that hydrocarbons found in lakes near oilsands development could have come from naturally eroding bitumen deposits.